1. Field of the Invention
The present invention relates generally to impact power tools. More specifically, the present invention concerns an impact power tool, such as a pneumatically powered, rotary valve controlled tool, for use in delicate hand working operations, such as detailed, precise, and fine engraving, carving, and stone setting work.
2. Discussion of Prior Art
Delicate hand working operations, such as detailed, precise, and fine engraving, carving, and cutting on metals, woods, stones, and the like, as well as stone setting work require an impact tool that delivers a low impact energy level for each stroke of the tool and that is capable of delivering such low impact strokes at a rapid rate. These problems have previously been identified in U.S. Pat. No. 4,694,912, assigned of record to the assignee of the present invention, issued Sep. 22, 1987 and entitled CONTROLLED IMPACT POWER TOOL (“Glaser '912 patent”) and hereby incorporated by reference herein.
The impact power tool disclosed in the Glaser '912 patent was an advance in the field and solved many of the problems identified in the art at the time. However, it has been determined that engravers and jewelry craftsmen increasingly are desiring to utilize larger hand piece attachments in their impact power tools, such as those capable of advanced carving applications on virtually any type of material, as well as desiring to utilize a wider range of hand pieces on the same impact power tool system for various and wide ranging applications. These desires are not being adequately met with the prior art impact power tools. In fact, craftsman desiring to perform multiple crafting applications that each require a different, wide range of power output must currently utilize multiple impact power tool systems to accomplish their tasks and even then, the combination of systems does not adequately address their desired ranges of power. Current impact power tool systems, particularly the use of multiple systems, undesirably consume valuable and limited inventory space on a craftsman's work bench.
Prior art impact power tools are also subject to other problems and limitations. For example, craftsman desire a crisp, quick, and immediate impact control adjustment. Such response time is simply lacking in prior art impact power tools. This problem is further frustrated by the craftsman's frequent “over-driving” of the tool—for example, when the craftsman is searching for the desired stroke speed or impact energy that is outside of the limits of the prior art tools. Accordingly, there is a need for an improved impact power tool.